Question

During the electrolysis process $4A$ electric current flows through a copper sulphate solution for $5$ minutes. Determine the number of copper atoms deposited at the cathode.

Answer 1

Step 1: Given data

Current, $i=4A$

Time, $t=5mins=300s$

Step 2: Determining the number of copper atoms deposited at the cathode.

Charge flowing in the given time $=i\times t$

$$\begin{gathered} =4\times 300 \\ =1200C \end{gathered}$$

Now, $1$ electron has charge $=1.6\times {10}^{-19}C$ of charge.

then, $1$ C of charge is contained by $625\times {10}^{16}$ electrons.

$1200$ C of charge is contained by $75\times {10}^{20}$electrons.

In constituents of copper sulphate is ${\mathrm{Cu}}^{2+}$ions. So, for $1$copper ions, we need $2$ electrons to neutralize it.

If we have $75\times {10}^{20}$electrons, then the number of copper ions that get deposited are $37.5\times {10}^{20}$${\mathrm{Cu}}^{2+}$ions.

Hence, the number of copper ions deposited is $3.75\times {10}^{21}$.